Snap switch for motor control



July 31', 1928.

1,678,725 R. M. GALLOWAY ET AL SNAP SWITCH FOR MOTOR CONTROL Original Filed Sept. 23, 1923 s Sheets-Sheet 1 WM gum/"tow 7 I E33) won wit WQM July 31, 1928; 1,678,725

R. M. GALLOWAY ETAL SNAP SWITCH FOR MOTOR CONTROL' Original'Filed Sept. 25, 1923 a Sheets-Sheet 2 Power? Lmz July31 1928. I 1,678,725

R. M. GALLOWAY ET AL SNAP SWITCH FOR MOTOR CONTROL Original Filed Sept. 23, 1923 Y 3 Sheets$heet 5 I K To MOTOR Patented July 31, 1928. i

UNITED STATES PATENT oFFicE.

ROBERT M. GALLQWAY, OF RICHMOND; INDIANA, AND PAUL C. BURTON, F CLAREN- DON HILLS, ILLINOIS, ASSIGNORS TO THE NATIONAL AUTOMATIC TOOL COMPANY, OF RICHMOND, INDIANA, A GORPORATIQN OF INDIANA.

SNAP SWITCH FOR MOTOR CONTROL.

Original application filed September 23,- 1923, Serial No. 661,447.,"Divided and this application filed April 7, 1925. Serial No. 21,375.

Inour pending application Serial No. and in part rendered apparent therefrom in 661,447, filed September 7, 1923 of which connection with the annexed drawings.

this application is a;,division, wehave shown To enable others skilled in the art so fully 55 and described a drilling machine including to apprehend the underlying features herea vertical standard, a drilLhead translatably of that they may embody the same in th mounted on the standard, a slow power feed various ways contemplated by this invento force the tools into the work and a rapid tion, drawings depicting a preferred typical traverse mechanism adapted to elevate and construction have been annexed as a part of 60 depress the drill-head to cause the tools rapthis disclosure and, in such drawings, like idly to recede from and approach the work. characters of reference denote corresponding This rapid traverse is actuatedby a reversparts throughout all the views, of which ible motor operatively connected with a pin- F1g- 1 a slde'elevation of a portion of ion, which engages a stationary rack affixed a lll g m hine embodying the present 05 to the vertical standard. Thus rotation of inventlon. Fig. 2 is a side elevation, partly. I 15 the motor effects translation of the head on In section of the improved snap-switch. the standard, the direction of movement of Fig. 3 1s a section'on the line 3-3 of Fig. 2, the head being determined by the direction wi h the switch in its neutral position. Fig. f t ti f th t 4; s a section on the line H of Fig.2. Fig. 70 The flow of electric current to the motor 1s a left end View of Fig. 2 with the parts to effect either forward or reverse rotation 11}. their neutral positions Fig. 6 is a view thereof is controlled by an electric switch limlar to Fig. 5' but showing the switch carried by the drill-head. This switch is, llf fll g parts in a position just ready to adapted to be actuated in timed relation effect an instantaneous breaking of the con- 75 with the movements of the drill-head by ots: F g. 6 is a detail view showing the suitable trip dogs carried by the machine position of certain locking lugs, later to be standard with which the switch actuating described, just prior'to the making of an lever comes in contact during its vertical electrlcal contact. Fig. 6 is a similar view movements. Manual means also is provided J Pr or tothe breaking of the contact. 80

to actuate the switch. 1g. 7 is aview similar to Fig. 6 but show- This invention relates more particularly 'lilg the parts in one of their extreme posito the switch for controlling the flow of curtlons. Fig. 8 is a detail section on the line rent to the reversible motor and to the means 88 of Fig. 2. Fig. 9 is a detail section on to actuate the switch, and has for an object the line 99 of Fig. 2. Figs. 10 and 1-1 are 85 to provide a reversing switch which is simdlagrammatic views illustrating the changes ple and durable in construction, which comin the connections between thepower line prises only a few parts and which will make and the motor which effect the reversal of and break the circuit instantaneously so that the motor. no sparking, or arcing, may occur between Referring more particularly to the'drau 90 the connector andthe electrical contacts lugs, the invention is disclosed as used in 40 which it connects. connection with a drilling machine compris- Another object is to provide a switch in ing a standard 1 upon which is translatably which an oscillatory connector has a neutral mounted the usual drill-head 2. As more position and two active positions and to profully set forth in our above noted applica- 95 vide both manual and automatic means to tion, Serial No. 661,447, this head is adapted actuate the switch, the automatic means beto be moved vertically on the column by ing adapted to be rendered eifective by vereither of two feeding mechanisms. One of tical movement of the switch selectively to these mechanisms commonly known as the oscillate said connector to any one of its rapid traverse is adapted to move the drill- 1 three positions in timed relation with the head rapidly to bring the tools to the work 5 reciprocation of. the drill-head. and v rapidly to'elevate the head after the Other objects and advantages will bein drilling or other operation. The other feedpart indicated in the following description ing mechanism, the slow power feed, is utilized to slowly feed the tools into the work while they are rotated by any suitable means. The rapid traverse mechanism includes a reversible motor 3 carried by the drill-head and operatively connected with a pinion (not shown) permanently in mesh with a rack 4: carried by the standard 1. As will readily be perceived, rotation of the motor in one direction causes the drill-head rapidly to be depressed and rotation ofthe motor in the opposite. direction causes the head rapidly to be elevated. The motor is preferably of the three-phase type and its direction of rotation may be reversed by changing twoof the three power lines leading thereto, as is usual with this type of motor. This change may bmeffected by means of a switch S carried by and vertically movable with, the drill-head 2. The switch is adapted to be actuated either manually or automatically as later will be described. p

The switch preferably comprises a housing it consisting of a lower body portion 5 and a detachable cover 6, both of which are lined with a suitable insulating material as. An arm 5 integral with the portion 5 serves to-support the housing from the drill-head 2. Within the bod portion 5 of the housing is journaled in earings 7 and 8, a shaft 9 upon which is fixed a drum 10 of insulating material. This drum is preferably built up of'a plurality of sections, 10 each having a reduced hexagonal end 10 which fits into a similarlg shaped socket 10 in an adjacent section. the sections 10 are contact segments 11, 12 and 13 adapted selectively to electrically connect in pairs contact fingers 14:, 15, 16, 17 18 and 19 carried by a block 20 of insulating materialsecur'ed in the upper portion of the'hou'sing 72.. As shown in Figs. 10 and 11 the fingers 14, 17 and 18 may-have connected to them wires a, b, and 0 constituting a suitable power line and the fingers 15, 16 and 19 may be connected to the reversible motor 3 by wires d, e. and f.

The shaft 9 and the contact segments carried thereby are adapted to occupy any one of three angular positions 'of which one is neutral, one produces forward rotation of the motor and the other produces reverse rotation thereof.v In one effective position of the parts as shown in Fig. 10 the wires ayb and c are connected respectively with the wires (1, "e and f as shown in heavy lines in Fig. 10, thus rotating the motor in a predetermined direction. In the other effective position of the parts as shown in Fig. 11, the wire a is connected with the wire e and the wire I) is connected with wire ii, the connection between the wires 0 and 7 being unchanged, .thus' the direction of rotation of the motor is reversed as is well understood by those skilled in-the art. The block ecured upon the reduced ends of between the contact fingers and the contact.

20 also carries a spring detent 'fin er .21 adapted to engage a detent notch 22 in the contactsegment 13 yielding. to hold the parts centrally in their neutral position. Joiirn'aled within the housing section 5, parallel with the shaft 9 and in bearings 23 and 24 is a switch actuating shaft 25 to one end of which is secured a crank 26 forming a part of a manual actuating means for the switch. A link 27 pivotally connected at one end to the crank 26 has its opposite end connected to one arm of a bell-crank lever H, fulcrumed on the drill-head within easy reachof the operator, whereby-he may conveniently oscillatethe shaft 25.and thereby, through an operative connection between that shaft and the shaft 9, actuate the switch.. As hereinbefore stated it is an object of this invention to provide means to actuate the switch instantaneously to prevent an arc segments. The present invention provides a very simple and effective means for accomplishing this result. This means consists of a load-and-fire mechanism between the shaft 25 and the shaft 9 and consists of only three parts viz. an actuating lever or arm 28 fixed to the shaft 25, a rocker 29 fixed to the shaft 9 and a coil spring 30 wound about the hub 29 of the rocker andshaft 25 that upon oscillation of the lever 28 the lugs are moved over the face 29' of the rocker and intersect the axis of the shaft 9. The rocker 29 is likewise provided on its face adjacent the lever 28, with locking lugs 33 and 34 arranged in the plane of the lugs 31 and 32 and adapted upon oscillation of I i the rocker to intersect the path of, and to come into contact with, the lugs 31 and 32. The lever 28 and the rocker 29 are provided with laterally extending arms 28 and 29" respectively arranged in substantial parallelism and extending between the spaced arms 30 30 of the spring 30. 'Stop lugs 35 and 36 integral with the housing 5 are adapted to engage the opposite faces of Formed I the arm 28 thereby to limit its movements, in opposite directions. ,Another stop-lug 37 provided by the has its opposite sides 37 and 37 arranged in the path of the heels 29 and 29 on'the rocker 29 to limit the extent of oscillation of the-rocker.

In addition to the manual means for'operating the switch there is also provided automatic means adapted to actuate the SW l Ch n timed relation With the reciproww tion of the drill-head on the standard- To this end the switch actuating lever 28 carries, intermediate its ends, a roller 38. During the vertical movements of the switch with the drill-head this roller is successively brought into contact with trip-dogs, or cams 39, 40, 41 and,42, adjustably secured upon 'a rod 43 carried by brackets 44 aid 45 secured to the standard 1.

Assuming that the motor 3 is rotating forwardly and the drill-head is being lowered by the rapid traverse, the "arms 26 and 28 will be in the positions shown in full and dotted lines respectively in Fig. l and the action of the cams 39, 40, 41 and 42 is as follows. Just prior to contact of the tools with the work the roller 38 engages the cam 39 which causes the lever 28 tobe swung to its central position thereby breaking contact between the contact segments and the contact fingers and bringing the rapid traverse" to rest.- The slow power feed then continues the downward movement of the drillhead but at a much slower speed. When the tools have penetrated the work to the desired depth the slow power feed is discontinued as the roller 38 engages the cam 40 which again shifts the lever 28 and throws the switch to a position in which current flows to the motor 3 to reverse its directon of rotation whereupon the rapid traverse mechanism rapidly elevates the drill-head until the roller 38 is brought into contact with the cam 41 adjacent the upper end of the rod 43. This cam again shifts the parts to their neutral position and discontinues the rapid upward movement of the drill-head. The momentum of the drill-heartland other moving parts will however, cause a limited upward movement of the drill-head after the roller and switch actuating lever have been brought to their neutral position, with the result that the roller engages the cam 42. This cam shifts the lever 28 and, through the rocker 29 and shaft 9, the contact segments are oscillated to a positiop whereinthey make the necessary contact with the contact fingers to again effect forward rotation of the motor wh ch results in a rapid down feed of the drill-head.

As hereinbefore described the connection between the shafts 25 and 3 is in the nature of a load-andsfire mechanism which effects instantaneous Zmake and break between the cont,a ct segments and the contact fingers.

The operation,of this device is as follows Assuming that the parts are in the position shown in Fig. 7 which causes the power feed wires a, Z) and c to be connected to the wires d, e and f 'as shown in Fig. 11 and that the drill-head is being elevated by. the

the cam. 41 shifts the lever counter-clockwise,

as viewed in Fig. 7. The initial movement v of the lever 28' rnoves the locking lug 32 in 31 and the are ac 6) which intersects theit the projecting end 30 of the spring 30 and inasmuch as the end 3O is-held against similar movement by the arm 29 of the rocker 29 the ends 30 and 30 are separated thereby winding the spring and storing power therein. Upon further movement of the lever 28 the point 32 of the lug 32 releases the point 34 of the lug 34 whereupon the power stored in the spring instantaneously rotates the rocker 29'the shaft 9 and the segments- 11, 12 and: 13 to throw the switch into its neutral position The separation of the contacts is effected with sufficient rapidity to prevent arcing, or sparking, between the contact fingers and the contact segments.

In throwing the segments into contact with the contact fingers the operation of the actuating lever 28, rocker 29 and the spring is substantially the same as above described except that the lug 32 passes beneath the lug 34 and prevents rotation of the rocker under the action of the spring until the point 32 of the lug 32 releases the point 34 of the lug The stop lug 36 is so located with respect to the arm 28 as to insure the separation of the lugs 32 and 34 before the arm contacts with the lug. Upon release of the manual shifting means or upon separation of the roller 38 from its actuating cams the power remaining in the spring retracts the arm 28 from the stop lug as shown in full lines in Fig. 7.

The operation of the parts in shifting the start the rapid up feed is similar to the operation above described except that the lugs 33 eifect the locking of the rocker and its subsequent release to permit the spring to shift the parts.

From the foregoing it will be perceived that this invention prot ides a three-position switch of simple construction which efi'ects quick make and break of the electrical circuit whereby the objectionable sparking between the contacts is precluded. Also thatthe invention provides both man ual and automatic means tooperate the switch, the automatic means being adapted to operate in timed relation with the reciprocation of the drill head.

WVit-hout further analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for various utilizations byret'aining one or more of the features that, from the standpoint of the "switch to stop the rapid down feed and to' prior art, fairly constitute essential characteristics of either the generic or specific aspects of this inventionand, therefore, such adaptations should be, and are intended to be, comprehended withinthe meaning and range of equivalency of the following claims Having thus revealed this invention, we claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the- United States:

1. An electric switch compirsing a housing; a plurality of fixed contacts in said housing; a first oscillatory shaft journaled in said housing; a contact member carried said shaft and adapted upon oscillation of the shaft selectively to connect said contacts; a second oscillatory shaft journaled in said housing parallel with said first shaft; manual means to oscillate said second shaft including an actuating crank secured to one end of said shaft; a lever'secured upon the opposite end ofsaid shaft; a rocker secured to said first shaft adjacent said lever; an operative connection between said lever and said rocker to transmit oscillatory movement from the second shaft to said first shaft; and a roller carried by said lever and adaptedto be acted upon by power means to shift said lever thereby to oscillate said firstshaft and the contact member carried thereby;

2. An electric switch comprising a housing; a plurality of fixed contacts in said housing; a first shaft journaled in said housing; a plurality of connectingvelements carried by said shaft and adapted selectively to electrically connect said contacts; a second shaft journaled in said housing at one side of said first shaft; a rocker secured to said first shaft and provided with two stop lugs and a spring-retaining arm; a coil spring surrounding said first shaft and having outwardly extending ends at opposite sides of said spring reta1ningarm; a lever fixed to said second shaft and provided with stop lugsand a laterally projecting springtensioning arm extending between the ends of said spring; means to move said lever first, to bring one of its lugs into contact with 7 one of the lugs on said rocker to hold said rocker against rotation, second, to store power in said spring and finally to disengage said stop lugs to permit said spring to turn said rocker and thereby turn said first shaft .an'electricalconnector carried by said shaft and the connecting elements carried thereby.

3. A snap switch comprising a support; a plurality of fixed contacts carried by said support; ashaft journaled in said support;

and adapted to electrically connect saidcontacts; a rocker secured upon one end of the rounding said shaft and having outwardly extending ends at opposite sides of said arms; and means to oscillate said lever with said lugs in contact, first to wind said spring and next to separate said lugs to permitsaid spring to rotate said shaft, instantaneously to separate said connector from said contacts.

4. A switch comprising a housing, a plurality of contacts in said housing; an oscillatory member journaled in said housing; a plurality of connectors carried by said member and adapted in different angular positions of said member to connect different pairs of said contacts; an actuating lever fulcrumed upon said housing at one side of said oscillatory member; two spaced sto'p lugs formed onsaid lever; a rocker secured upon said oscillatory member; two lugs on the face of said rocker adjacent said lever and in the vertical plane of said stop lugs, the lugs on said lever and on said rocker being-so arranged that upon oscillation they move in intersecting" areuate paths; a spring connection between said lever and said rocker; means to oscillate sald lever and through said lever and spring connection to oscillate said rocker to bring two of said lugs into contact, said lugs acting temporarily to hold said rocker against rotar'y'movement while a continued movement of the lever stores power in said spring; and means to separate said lugs to permit said spring to turn saidoscillatory member.

5. A three position electric switch having reversing and neutralpositions comprising a series of electrical contacts; a member carrying a pluralit of connecting elements adapted selective y to connect in pairs' said contacts; an actuating shaft; an arm carried .by said shaft; a rocker on said member; a

spring interposed between said arm and said rocker to transmit to the latter power from the former; and ,co-acting lugs carried by saidbarm and rocker and adapted to be brought together by-movement ofthe arm to hold said rocker against movement until said arm has reached a predetermined position.

In witness whereof, we have hereunto subscribed our names.

ROBERT M. GALLOWAY. PAUL 'C. BURTON. 

